Get ready for a week of heatwaves

With the mercury set to soar above 30C across all capital cities, except Hobart, in the days ahead, Aussies are urged to slip, slop, slap and stay out of the heat. Even Tasmania won't be far off the 30C mark.

Perth could get to 35C, Melbourne 36C and Adelaide a suffocatingly hot 38C.

Bureau of Meteorology meteorologist Ashleigh Langey said NSW would reach peak temperatures on Thursday, followed by a short cool change on Friday.

"Over the next couple of days there will be a high pressure system influencing the state with pretty warm conditions. From Tuesday onwards it looks like we have got a low intensity heatwave developing, and by Thursday it will be a severe heatwave in parts of the state.

"There will be clear skies as well, which means things will heat up."

Western Sydney will bear the brunt of the hot weather, climbing to 42C near Penrith and remaining in the mid to high 30s throughout the week.

"The hottest day in Sydney will be Thursday, and we're forecasting 34C (and hotter in the west). On Friday it will cool down to 27C because we have a southerly change moving through that will cool things down a bit," she said.

"Even on Friday in the west of NSW it will still be quite warm. On Saturday it's heating back up with 33C in Sydney."

It's a trend we'll see happening Australia-wide this week, with all states and territories in for 30C or warmer except Tasmania.

BRISBANE:

The temperature will be in the high 20s with possible showers early in the week, followed by a sunny 32C on Friday and Saturday.

SYDNEY:

Sydney will enjoy sunny days with temperatures in the high 20s before hitting a high of 35C s on Thursday followed by a late shower which will bring temperatures down into the 20s again for the rest of the week.

But it will be a different story in western Sydney, with Penrith sweltering through a week of temperatures in the 30s, reaching 41C on Thursday.

CANBERRA:

The nation's capital is set to swelter this week, with a low of 30C on Monday followed by five days of temperatures in the low to mid 30s. It will hit a peak of 34C on Thursday, followed by showers until Saturday.

MELBOURNE:

It will be partly cloudy for most of the week in Melbourne, with temperatures in the mid to high 20s most days, with the thermometer topping 36C on Wednesday.

ADELAIDE:

It will be a warm few days in Adelaide, reaching a sunny 36C on Tuesday followed by cloud and a high of 38 Con Thursday. Temperatures will then drop to the mid to high 20s for the following three days.

DARWIN:

Darwin will hit 35C all week except Friday, when it will reach 34C.

PERTH:

It will be 35C with a possible shower in Perth on Monday, followed by a few days in the high 20s before reaching 30C again on Friday.

HOBART:

Hobart will be the only capital that doesn't reach the 30 degree mark, hitting a high of 29C on Wednesday. Temperatures will stay in the mid 20s for most of the week.